Different error message from MySQL when group by a window function with a as

[time-and-fate]

Bug Report

1. What did you do?

In a select stmt, group by a window function using its asname.

2. What did you expect to see?

In 8.0.19 MySQL Community:

MySQL [test]> select row_number() over () as x from t group by x;
ERROR 1056 (42000): Can't group on 'x'

3. What did you see instead?

In TiDB:

MySQL [test]> select row_number() over () as x from t group by x;
ERROR 1247 (42S22): Reference 'x' not supported (reference to window function)

4. What version of TiDB are you using? (tidb-server -V or run select tidb_version(); on TiDB)

Release Version: v4.0.0-beta-710-gac8785a97